Electric fan



Dec. 22, 1953 c. J. BURKLA'ND ELECTRIC FAN Filed Sept. 6, 1950 Patentedec. 22, 1953 ELECTRIC FAN Carl J. Burkland, Chicago, Ill., assignor ofone.- half to Earl Haubrich, Chicago, Ill,

Application September 6, 1950, Serial No. 183,387 7 Claims. (01.230-259) This invention is concerned with an electric fan, and moreparticularly, with structure for reversing or otherwise varying thepitch of the fan blades.

Conventional electric fans are provided with fixed blades and arepowered by constant speed motors. The air stream that is available fromsuch fans is necessarily fixed in intensity and can be varied indirection only by reversing the position of the fan. Some more expensivefans in permanent installations are provided with re.- versible motorsso that an air stream can be di rected either forwardly or reversely ofthe fan. The available air stream cannot be varied in in tensity and hasonly two possible directions.

An important object of this invention is the provision of an electricfan having blades of variable pitch whereby the intensity of the airstream delivered can be varied over a wide range.

Another object of this invention is the provision of an electric fanhaving blades. of reversible pitch whereby an air stream can be directedeither forwardly or reversely of the fan without reversing the directionof rotation of the fan motor and without reversing the orientation ofthe fan.

A further object of this invention i the. provision of an electric fanwherein the pitch of the blades can be varied over a continuous rangefrom an extreme forward to an extreme reverse position while the fan isoperating.

Yet another object of this invention is the provision in an electric fanof a pair'of concentrically mounted drive shafts shiftablelongitudinallyrelative to one another and carrying blades, the:

pitch of which is varied by linkage actuated: by relative longitudinalshifting of the concentric shafts.

A further object of this invention is the provision in an electric fanof a pair of concentrically mounted drive shafts shiftablelongitudinally relative to one another to vary the pitch of the.

fan blades wherein one of the shafts is fixed.

longitudinally and the other shaft is shiftable. longitudinally by meansof a member secured thereto by a ball bearing structure to reducefriction and th member can be locked in any position to maintain the fanblades at any de-- sired pitch.

Other and further objects and advantages of the present invention willbe apparent from the following description, when taken in connectionwith the accompanying drawing, wherein:

Figure 1 is a partial side view of an electric fan embodying theprinciplesof my invention;

Figure 2 is a view taken from the right: end of Figure 1;

Figure 3' is a longitudinal sectional view taken substantially along theline III-III of Figure 1;

Figure 4 is a side view showing the pitch actuating mechanism; and

Figure 5 is a cross sectional view taken substantially along the lineV-V of Figure 3.

An electric fan embodying the principles of my invention comprises theusual motor enclosed in a motor casing '6 and held together by elongatedbolts ii extending longitudinally through the casing. The armature ll]of the motor is mounted on a hollow drive shaft I 2 journaled inanti-friction bearings M carried by the motor casing G. The bearings Mare preferably ball bearings and are adapted to prevent longitudinalmovement of the shaft I2, while allowing substantially frictionlessrotational, movement.

A fan blade carrying member [6 comprising generally a pair of coaxialcylinders l8 and 2t spaced by an end wall 22 is secured to the forwardend of hollow drive shaft 82 for rotation therewith by means such as oneor more set screws 2E. A plurality of fan blades 26 are carried by themember it. Each blade is secured to or is formed integrally with a stubshaft 28 extending through an. aperture in the outer cylinder 20 andhaving its inner end received in a shallow aperture 39. A, cylinder 32fits on the inner end of each stub shaft 28 abutting the inner surfaceof the outer cylinder 20 and secured thereon by a nut 34. An arm 36.extends transversely from each cylinder 32, and each cylinder 32 isprevented from rotating relative to the stub shaft on which it ismounted by means of a set screw 38.

An elongated shaft 46 is concentrically mounted within the hollow driveshaft 12 and extends bothforwardly and reversely therefrom. A circularplate 42 is secured at the forward end of the shaft 40,. by means suchas a left hand thread and a. set screw 44 threaded. into an integral hub46 of the. plate 21 A plurality of pins 48 equal in number to. the fanblades are symmetrically disposed. about: the periphery of the plate 52and are. ang-ularly offset slightly from. the fan blades.

Each pin is. provided with an integral collar 5a which, in cooperationwith. a nut 52, secures the pin in position in an aperture through theplate 42.. Each pin 43 is connected to one of the arms. 35- by means ofa link. 54. Each link 54 is bifurcatedat the opposite ends toaccommodate anarm 36 and one of the pins. 48 and is pivotally connectedto this arm and pin. by means of a transverse screws pin orrivet, 5,6.

A cup-shaped housing 58 is secured to the blade mounting member [6 andcovers the plate 42, the structure linking the plate to the fan blades,and the end of the inner shaft 40. The housing 58 may be secured to theblade mounting member or structure [6 by screws, or by any othersuitable means.

The rear end of the inner shaft 40 extends rearwardly from the motorcasing B and a cylinder 80 is mounted concentrically and in spacedrelation therewith. The cylinder 69 is secured to'the motor housing bymeans of a peripheral fiange 52 through which the elongated bolts 8securing the motor together pass. A sleeve 64 having a peripheralfiangefifi is mounted on the rear end of the shaft 58 within thecylinder 69. A collar 68 on the sleeve 54 clamps the inner race 10 of aball bearing structure against the flange 66. A set screw 72 extendsthrough the collar 68 and the sleeve 64 and bears against the shaft 40to lock these members in proper relative positions. A key (not shown)may be provided to prevent relative rotation of the race it and thesleeve 64, although the clamping connection generally will be foundsufiicient.

A collar I4 having an inwardly directed arcuate flange is positionedover the outer race 13 of the ball bearing structure and is secured inposition by a clamping ring 80 afiixed to the collar 14 by a pluralityof spaced screws 82. Relative rotation of the collar 14 and the outerrace 18 is precluded by the clamping connection and by a set screw 83threaded into the collar it and bearing against the race. A threaded rod84 is threaded into a radial aperture in the collar 14 and also into alongitudinal aperture in the head of a cap screw 8%. The shank of thecap screw extends through a substantially diagonally disposed slot 88 inthe cylinder 60 with the underside of the head of this screw abuttingthe inner face of the cylinder. A control knob 90 which preferably has aknurled periphery is threaded on the shank of the cap screw 86, and whentightened, clamps the cylinder to between it and the head of the screw86.

When the fan is operated, the hollow drive shaft I2 is rotated as is theblade mounting structure or member is. The inner shaft 40 rotates withthe outer shaft and a splined connection may be provided between thesetwo shafts for this purpose, although this is unnecessary with smallfans as the plate 32 and structure linking this plate to the fan bladeswill rotate the inner shaft readily. The cylinder 60 extending from therear of the fan motor is stationary and the collar 14 and outer race 18of the ball bearing structure is likewise stationary due to the clampingconnection between the nut 99 and cap screw 85. If it is desired tochange the pitch of the fan blades, it is only necessary to loosen thenut 90 and to revolve it about the shaft iii. The diagonal slot 88forces the cap screw 86 toward or away from the motor casing 6,depending upon which direction the nut 90 is shifted about the shaft toand cylinder til. The forward or rearward shifting of the cap screw 86causes the shaft 40 to move longitudinally either forwardly orrearwardly relative to the hollow drive shaft 12. This, in turn, shiftsthe plate 42 forwardly or rearwardly. Assuming that the plate 42 isshifted rearwardly from the solid line position of Figure 4 to thedashed line position of Figure 4, it will be seen that the pivotallinkstd will act through the arms 35 to rotate the cylinders or sleeves32 and thus shift the pitch of the blades 25. As shown in Figure 4, theplate 42 is moved from its extreme forward to its extreme rearwardposition, thus completely rever ing the pitch of the fan blades 25 asshown in solid and in dashed lines; The cap screw 8% can be positionedat any point intermediate the ends of the diagonal slot 88 to providethe blades with a steep or a shallow pitch for delivering an air streamof variable intensity either forwardly or rearwardly of the fan.Tightening of the nut 99 to clamp the cylinder 60 between the nut andthe head of the cap screw 86 will lock the fan blades in position withany desirable pitch. The pitch of the fan blades may be altered whilethe fan is operating so that the blades may be adjusted to give anydesirable air stream without the necessity of positioning the blades atany predetermined pitch.

said hollow drive shaft from said blade mounting member and driventhereby, said fan blades being rotatable about their longitudinal axes,a second shaft concentrically mounted within said hollow drive shaft andextending forwardly thereof, said second shaft being rotatable with saidhollow drive shaft and said shafts being freely shiftable axially of oneanother, an actuating member fixed on the forward end of said secondshaft, a plurality of links between said actuating member and the innerends of said fan blades for shifting the pitch of said blades inresponse to movement of said actuating member toward or from saidblades, a positioning lever extending substantially radially from therear end of said second shaft and rotatable relative thereto, and meansdefining a fixed guideway obliquely disposed relative to said secondshaft and receiving said positioning lever to shift said second shaftforwardly or rearwardly of said hollow drive shaft as said positioninglever is rotated relative to said guideway.

2. An electric fan comprising a motor, a rotatable hollow drive shaft insaid motor, a blade mounting member fixed on the forward end of saidhollow drive shaft for rotation therewith, a plurality of bladesextending radially of said hollow drive shaft and carried by said blademounting member, said blades being rotatable about their longitudinalaxes, a second shaft concentrically mounted within said hollow driveshaft and extending forwardly and rearwardly therefrom, said secondshaft being rotatable with said hollow drive shaft and said shafts beingfreely shiftable axially of one another, an actuating member fixed onthe forward end of said second shaft, a plurality of 1inksinterconnecting said actuating member and said blades for rotating saidblades about their axes to determine the pitch of said blades, a fixedcylinder extending rearwardly from said motor concentric with saidsecond shaft and spaced therefrom, said cylinder having a guideway ob,liquely disposed relative to said second shaft, and aposition-determining lever extending substantially radially from saidsecond shaft near the rear end thereof and fitting within said guide:

way, said position-determining lever being rotatable relative to saidsecond shaft but fixed against movement longitudinally of said shaftwhereby rotation of said position-determining lever will shift saidlever and second shaft longitudinally relative to said hollow driveshaft to shift the pitch of said blades.

8. An electric fan comprising a motor, a retatable hollow drive shaft insaid motor and extending forwardly therefrom, a blade mounting membersecured on said hollow drive shaft forwardly of said motor and rotatablewith said shaft, a plurality of blades extending radially of said hollowdrive shaft and carried by said blade mounting member, a lever arm oneach of said blades, a second shaft concentrically mounted within saidhollow drive shaft and extending rearwardly and forwardly therefrom,said second shaft being rotatable with said hollow drive shaft and saidshafts being freely shiftable axially of one another, an actuating member secured on the forward end of said second shaft, a plurality ofpivotal links interconnecting said actuating member and the lever armson said blades to pivot said blades about their longitudinal axes andthereby adjust their pitch upon movement of said actuating member towardand away from said blade mounting member, means defining a fixedguideway carried by the rear of said motor with said guideway obliquelydisposed relative to said shafts, and a position-determining lever carrid by the inner shaft and fitting within said guideway to shift saidshafts longitudinally relative to one another to adjust the pitch ofsaid blades upon relative rotation between said guideway-determiningmeans and said position-determining lever.

4-. An electric fan comprising a motor, a retatable hollow drive shaftin said motor and extending forwardly therefrom, a blade mounting membersecured on said hollow drive shaft adjacent the forward end thereof, aplurality of blades extending radially of said hollow drive shaft andcarried by said blade mounting member, a lever arm on each of saidblades, a second shaft concentrically mounted within said hollow driveshaft and extending forwardly and rearwardly therefrom, said secondshaft being rotatable with said hollow drive shaft and said shafts beingfreely shiftable axially of one another, an actuating member fixed onthe forward end of said second shaft, a plurality of pivotally mountedlinks interconnecting said actuating member and the lever arms on saidblades to pivot said blades and adjust the pitch thereof, a fixedcylinder extending rearwardly from said motor and radially spaced fromsaid second shaft, said cylinder having a fixed guideway obliquelydisposed relative to said shaft, a position-determining lever on saidsecond shaft fixed against movement longitudinally of said second shaftand rotatable relatively thereabout, said position-determining leverfitting within said guideway and shifting said second shaft forwardlyand rearwardly of said first shaft to adjust the pitch of said bladesupon rotation of said position-determining lever and means for lockingsaid position-determining lever and said cylinder to preventlongitudinal movement of said second shaft.

5. An electric fan comprising a motor, a rotatable hollow drive shaft insaid motor and extending forwardly therefrom, a blade mounting member onsaid hollow drive shaft including a pair of spaced concentric cylindersinterconnected at one end by a transverse wall and open at the otherend, the outer of said cylinders being provided with a plurality ofarcuately spaced apertures and the inner of said cylinders beingprovided with a plurality of recesses aligned radially with saidapertures, a plurality of fan blades, a rod extending longitudinallyfrom the inner end of each of said fan blades, each of said rodstraversing the space between said cylinders and being received in one ofsaid apertures and one of said recesses, abutment of said rods in saidrecesses preventing inward movement of said rods, a locking member oneach of said rods within the outer of said concentric cylinderspreventing outward movement of said rods, a second shaft concentricallymounted within. said hollow drive shaft and extending forwardlytherefrom, an actuating member secured on the forward end of said secondshaft forwardly of said blade mounting member, a plurality of linksinterconnecting said actuating member and said rods for rotating saidrods to adjust the pitch of said fan blades upon movement of saidactuating member toward or away from said rods, and means for shiftingsaid second shaft and said hollow drive shaft longitudinally relative toone another.

6. An electric fan comprising a motor, a rotatable hollow drive shaft insaid motor and extending forwardly therefrom, a blade mounting member onsaid hollow drive shaft including a pair of spaced concentric cylindersinterconnected at one end by a transverse wall and open at the otherend, the outer of said cylinders being provided with a plurality ofarcuately spaced apertures and the inner of said cylinders beingprovided with a plurality of recesses aligned radially with saidapertures, a plurality of fan blades greater than two, a rod extendinglongitudinally from the inner end of each of said fan blades, each ofsaid rods traversing the space between said cylinders and being receivedin one of said apertures and one of said recesses, abutment of said rodsin said recesses preventing inward movement of said rods, a lockingmember on each of said rods within the outer of said concentriccylinders preventing outward movement of said rods, a lever arm on eachof said looking members, a second shaftv concentrically mounted withinsaid hollow drive shaft for rotation therewith and shiftable freelyaxially thereof and extending forwardly and rearwardly therefrom, anactuating member on said second shaft mounted forwardly of said mountingmember, a plurality of links interconnecting said actuating member andsaid lever arms to rotate said rods upon movement of said actuatingmember toward or away from said rods to adjust the pitch of said fanblades, a substantially cupshaped housing interfitting with the outer ofsaid concentric cylinders and enclosing the forward end of said secondshaft, said actuating member, said pivotal links, and said lever arms,means on the rear of said motor defining a fixed guideway obliquelydisposed relative to said shafts, and a position-determining levermounted on said second shaft and fixed against movement longitudinallyof said second shaft, said positiondetermining lever fitting within saidguideway and shifting said second shaft upon rotation thereof relativeto said guideway-defining means.

7. An electric fan comprising a motor, a rotatable hollow drive shaft insaid motor and extending forwardly therefrom, a, blade mounting memberon said hollow drive shaft including a pair of spaced concentriccylinders interconnected at one end by a transverse wall and open at theother end, the outer of said cylinders being provided with a pluralityof arcuately spaced apertures and the inner of said cylinders beingprovided with a plurality of recesses aligned radially with saidapertures, a plurality of fan blades greater than two, a rod extendinglongitudinally from the inner end of each of said fan blades, each ofsaid rods traversing the space between said cylinders and being receivedin one of said apertures and one of said recesses, abutment of said rodsin said recesses preventing inward movement of said rods, a lockingmember on each of said rods within the outer of said concentriccylinders preventing outward movement of said rods, a lever arm on eachof said locking members, a second shaft concentrically mounted withinsaid hollow drive shaft for rotation therewit and shiftable freelyaxially thereof and extending forwardly and rearwardly therefrom, an actuating member on said second shaft mounted forwardly of said mountingmember, a plurality of links interconnecting said actuating member andsaid lever arms to rotate said rods upon movement of said actuatingmember toward or away from said rods to adjust the pitch of said fanblades, a substantially cup-shaped housing interfitting with the outerof said concentric cylinders and enclosing'the forward end of said sec-8, ond shaft, said actuating member, said pivotal links, and said leverarms, a cylinder fixed on the rear of said motor concentric about saidsecond shaft and spaced from said second shaft, said cylinder having aguideway obliquely disposed relative to said second shaft, apositiondetermining member on said second shaft adjacent the rear endthereof, said position-determining member being fiXed against movementlongitudinally of said second shaft and rotatable relative thereto, saidposition-determining member fitting Within said guideway and shiftingsaid second shaft forwardly and rearwardly of said hollow drive shaftupon rotation of said positiondetermining member about said secondshaft, and radially shiftable means for locking saidpositioncletermining member in said guideway to maintain constant thepitch of said fan blades.

CARL J. BURKLAND.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,278,396 Speiser Sept. 10, 1918 1,779,050 Schroder Oct. 21,1930 1,887,045 Schwarz Nov. 8, 1932 2,150,129 Pecker Mar. 7, 19392,478,244 Cooley Aug. 9, 1949 2,514,097 Sharp July 4, 1950

